This application is for an amended institutional NRSA to support the training of four M.D., M.D./Ph.D., or Ph.D. post-doctoral fellows for research careers in the multi-disciplinary field of the pathobiology of the developing cardiovascular system. Research trainees will spend 3 years in the laboratory of an experienced mentor. The training faculty consist of 19 investigators with different departmental backgrounds but whose laboratories have an established interest in the cardiovascular system and technical expertise in state-of-the-art methodology. These areas include developmental molecular biology, gene expression and bioinformatics, immunobiology, gene targeting in mouse models, molecular biology, molecular genetics of human cardiovascular disease, muscle molecular biology, tissue engineering and vascular biology. The selected mentors include many senior scientists with documented experience in postdoctoral training. The structure of the training program is designed to promote interactions between participating faculty and to provide trainees with access to all the laboratories and their considerable resources. Trainees will be selected from graduate and clinical programs nationwide with an emphasis on identifying those individuals with the potential to become independent investigators. The major component of the training program is independent research carded out by trainees in their laboratories of choice. A system of preceptors and secondary mentors will ensure a strong training experience. A unique feature of the program is that the strong laboratory experience is coupled with didactic training in the Cardiac Registry at Children's Hospital. The Registry is an extremely valuable teaching resource that has provided students with new insights into many forms of congenital heart disease. The amended program plan includes specific steps for minority recruitment, as well as specific programs for responsible conduct of research. The long-term goal of this program is to attract and train individuals for academic careers in the cardiovascular system. As has frequently been the case, scientists and clinicians often cross-fertilize each other, leading to translational research opportunities and better patient care.